The lunchroom at Aspire Preparatory Middle School in The Bronx can erupt in a split second over issues like girlfriends, boyfriends or any little thing.

“A group of people will just be looking at another group, and out of nowhere there’s a huge fight,” said eighth-grader Chitra Jaipersud, 12. ”I’ve seen girls pull each other’s hair out.”

The Williamsbridge junior high is one of seven city schools newly added to this year’s list of “persistently dangerous” schools, which was quietly posted on the state Education Department’s Web site last week.

Of 19 schools statewide on the 2011-12 list, nine are in New York City. It’s a big improvement from last year, when 12 of 16 schools named were in the city.

The nine are middle and elementary schools, including four in The Bronx — Aspire, Soundview Academy for Culture and Scholarship, PS 11 Highbridge, and IS 190; two in Brooklyn — Middle School for Academic and Social Excellence, and PS 12 in Brownsville; and three in Manhattan — PS 194 Countee Cullen, JHS 13 Jackie Robinson, and MS 332 University Neighborhood.

For a spot on the list, schools rack up six or more “serious incidents” for each 100 pupils two years in a row.

Under the No Child Left Behind Act, parents can seek to transfer their kids.

Aspire Prep, which has 554 students, tallied 88 “violent and disruptive” incidents in 2009-10, including 10 sex crimes, a robbery, 21 assaults and 38 “minor altercations.’’ State education officials have not yet posted last year’s data.

The middle school is also plagued with after-school brawls, kids said. Eighth-grader Diego Cortez, 12, recalled a rumble right outside the school gate.

“One girl wanted to fight another girl. Then the girl got six girls to jump her,” Cortez said, adding he was scared when “half the school” gathered to watch like it was a wresting match.

Two of the nine city schools were on the list last year — JHS 13 and MS 332.

“Last year there was a lot of fighting,” said a soft-spoken 11-year-old in the seventh grade at MS 332 on the Lower East Side.

“Every school has bad kids who want to act out and lash out. They are the few who ruin it for the bunch,” said Elijah Moore, 14, who graduated from MS 332 last year and attends Urban Assembly Academy for Government and Law HS in the same building. The aspiring lawyer defended his middle-school alma mater.

“Whenever anything happens, they have to report it. That’s what good teachers do. But then the school is called bad,” he said.

Marge Feinberg, a spokeswoman for the city Department of Education, said some of the nine schools “made great progress” in stemming the mayhem. But since last year, under tighter rules, schools have to stay on the list for at least two years before they can petition the state to be removed.